What is relationship in database management system?

Answer 1

A relationship is an association between the instances of one or more entity types. For example, a student may be related to a class by being enrolled in that class. Another example is the link between mother and children. One mother may have many children, but each child has only one mother.

A relationship between entities is given a relevant name. For example, there is a relationship between MANAGER and DEPARTMENT. A manager manages the department; on the other hand a department is managed by a manager. This leads to a relationship called "Manages" between MANAGER and DEPARTMENT.

Similarly, there is a relationship between AUTHOR and the BOOK. An author writes a book; on the other hand a Book is written by an Author. This leads to a relationship called "Writes" between AUTHOR and BOOK